Light-emitting diodes (LEDs) are semiconductor light sources used in a variety of applications, including general lighting, street lighting, and automotive lighting, to name a few. LEDs emit light through an electroluminescence effect, whereby electrons and holes in a material, typically a semiconductor, recombine, causing the electrons to emit energy in the form of photons, or light. LEDs are advantageous over incandescent light sources because they consume less energy, have a longer lifetime, emit stronger light output, and are smaller in size.
One contributing factor in maintaining the long life of an LED is temperature regulation. High-power LEDs are subjected to higher junction temperatures, sometimes as high as 150° C., which cause stress on the material. Thus, LED performance is temperature-dependent. One way to structure an LED package in order to regulate its temperature is to use a thermal substrate. The majority of high power/high brightness (HP/HB) LED circuits manufactured today are based on Metal Core Printed Circuit Board (MCPCB) technology. The MCPCB system consists of a copper foil, which acts as the circuit layer, a polymer dielectric layer, and either an aluminum or copper base layer that acts as the thermal substrate. The aluminum or copper substrate has excellent thermal conductivity and provides for thermal dissipation away from the circuitry. The polymer dielectric layer electrically insulates the copper foil from the thermal substrate, while also having good thermal conductivity to allow the heat to be transferred to the thermal substrate.
The MCPCB system is typically manufactured using a subtractive process, whereby the copper foil, dielectric layer and thermal substrate are laminated together, and the copper foil is then chemically etched to create the desired electrical pattern to form the circuit layer. This process can be costly, as it is labor intensive and there is a significant amount of material waste through the copper etching process.
Therefore, an electroconductive component is needed that is simple to manufacture, has optimal heat dissipation properties, and reduces the amount of material waste resulting from the formation of the electrical leads. It preferably also results in the formation of dense fired leads that are highly conductive. The material used for the circuitry preferably is able to be processed at temperatures less than about 610° C., as aluminum substrates begin to distort at temperatures above 620° C. Further, the circuitry should adhere well to the dielectric layer. Lastly, the ideal LED system preferably performs well under a variety of environmental conditions, including automotive and outdoor uses.